Project Summary/Abstract Hypertension is a cardiovascular disease (CVD) risk factor of unquestionable importance. Older adults are disproportionally affected by hypertension with two thirds of adults 60+ years of age in the U.S. having hypertension. The CVD reduction benefits of antihypertensive medication have been demonstrated among older adults with hypertension. However, accumulating data suggest antihypertensive medication intensification may be associated with an increased risk of falls among older adults with hypertension. As falls are associated with substantial morbidity and mortality in older treated adults with hypertension, clinicians are wary about intensifying antihypertensive medication in this population. Clinic blood pressure (BP) is among the factors used by health care providers in the decision-making regarding antihypertensive medication intensification. However, BP outside of the clinic setting can be lower than clinic BP and have large fluctuations throughout the day. Therefore, out-of-clinic BP may be a more clinically relevant physiologic measure linked to falls. Ambulatory BP monitoring (ABPM) quantifies out-of-clinic BP over a 24-hour period in the naturalistic setting. ABPM can be used to assess the white coat effect, defined as the difference between clinic and ambulatory BP, and white coat hypertension, defined as having elevated clinic but non-elevated ambulatory BP. ABPM can also assess the magnitude of BP variability over 24 hours as well as postprandial BP decline, the BP decline following meals. The aims of this study are to determine whether a larger white coat effect and BP variability over 24 hours and secondarily, postprandial BP decline are associated with an increased risk of falls among older treated adults with hypertension. Further, the study will also identify the demographic and clinical factors associated with a larger white coat effect, BP variability, and postprandial BP decline. To address these aims, we will enroll 1057 patients 65+ years of age from Kaiser Permanente Southern California who have a history of hypertension and are taking antihypertensive medication. Demographics, clinical characteristics, geriatric assessments (frailty, impaired cognition, mobility, functional impairment and physical performance), and 24-hour ABPM will be performed at baseline. Falls and serious fall injuries (fractures, joint dislocations, and brain injuries) will be assessed prospectively over a 1-year follow-up period. When deciding to intensify antihypertensive medication, health care providers and patients are faced with trade-offs between the potential for preventing CVD events vs. the possibility of increasing falls. As out-of-clinic BP may be a more relevant physiologic measure of fall risk than clinic BP, ABPM holds great promise as a tool to support individualized care for older treated adults with hypertension. ABPM may have an essential role for identifying older adults with hypertension in whom antihypertensive medication intensification can safely be undertaken or otherwise avoided.